Modeling Resilience to Stormwater During Extreme Weather is a scientific screening tool to help cities understand the impact of stormwater during extreme weather events.

Information from the app can be used to:

  • Identify areas, infrastructure, public buildings, and residences vulnerable to stormwater and flooding during extreme weather events
  • Make plans to invest in and maintain critical infrastructure with future precipitation patterns in mind

Get Started by entering rainfall to view change in runoff volume compared to a baseline storm
Enter The App!
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This App, developed by Stone Environmental, Inc., for the Esri Global Disaster Resilience App Challenge 2014, provides high-resolution information on runoff accumulation in relation to key infrastructure, public and residential buildings, and flood zones that can be used to influence disaster preparedness policy or to make planning decisions.

Accumulated runoff from user-defined rainfall is compared to runoff generated by a baseline storm to estimate stormwater volume that may exceed the current capacity of city infrastructure. Predictions of vulnerable areas can then be used to prioritize investments to prevent flooding, road damage, and other consequences of infrastructure failure.

The App was created in support of Essential 3 and Essential 4 of the United Nations Office for Disaster Risk Reduction’s Essentials for Making Cities Resilient.

While the app focuses on Barre, Vermont as the pilot city, this template could be applied anywhere in the world where the relevant spatial data sets are available.

To get the app for your city, email


This tool has been developed using a variety of tools!

The front-end was built using the ESRI ArcGIS Javascript API, the DOJO javascript framework, and the Google charting API.

The back-end of this tool is based on ArcGIS Server 10.2.2 and a PostGreSQL-based ArcSDE-enabled database. The front-end interacts with the back-end using the ArcGIS Server REST API to retrieve the various map images. There is a custom GeoProcessing service written with Python that provides the results of the flow accumulation modeling.

This tool was built buy our team over a 10-day stretch.

Imagery used was developed in-house.


Stone Environmental's Applied Information Management group loves creating powerful, scientifically accurate tools for our clients across the full spectrum of system platforms. Across those platforms, we use ArcGIS pervasively to help collect, maintain, process, analyze, and interact with the data.

This project's development team is:

  • Alan Hammersmith
  • Barb Patterson
  • Charlie Hofmann
  • Katie Budreski
  • Kelsey Lanan
  • Lauren Padilla
  • Mike Winchell
  • Naresh Pai
  • Nick Floersch
  • And Our Fearless AIM Team Leader!

  • David Healy


The ‘Change in Runoff Accumulation” is based on the difference in total storm runoff of a 10-year storm versus the user defined storm. The 10-year storm is assumed to be a baseline for infrastructure capacity, particularly for older systems. If your infrastructure is older and is in an area with a large increase in flow, there is risk of failure during an extreme event.

Depending on the duration of the storm, the estimated increase in flow rate through locations will vary. Linear estimates of flow rates like those shown below can be used to approximate the order of magnitude of the additional flow compared to baseline capacity.

If the predicted change in total storm runoff is an increase of 818,676 gallons for a location, you can expect the following increase in flow past that point:
Storm Duration (hours) Gallons per Hour Cubic Feet Per Second (cfs)
6 136,446 5.1
12 68,223 2.5
24 34,112 1.3
48 17,056 0.6

Note that, as a screening tool, flow diverted by infrastructure is not accounted for in these estimates of runoff volume and flow rate. Actual rates will also vary throughout the storm with variations in rainfall intensity and depending on surface roughness, slope, and flow patterns in the watershed.

Help & Use
Residential Buildings
Public Buildings
Stormwater Infrastructure
Bridges & Culverts
Stormwater Lines
Flood Zones

Or select from recent storms:

The 'Change in Runoff Accumulation' highlights areas that may exceed the capacity of infrastructure designed to a 10-year 24-hour storm. The increase in runoff from the user-defined storm compared to the 10-year storm is shown in the map.

3.27"10-Year Storm
0"Selected Storm

Analyzing all soils and landuse data to calculate runoff accumulation. This might take a few seconds...